Method of dewaxing oils



June 18, 1935.

J. W. WEIR METHOD OF DEWAXING OILS Filed July 26, 1928 NNN NINA'.

Patented'June 18, 1935" V l l I 1 UNITED A,sf'jrA*Tias. PAIENT; oFFicE mesne assignments, to '1 l1e` Texas Company,:

New York, N. Y., acorporation of Delaware ApplicationJuly 26, 1928,Serial No. 295,464` 'i f f 1112' .Cleins- (C1. y19t-1li) i' o I o yThisinvention relates to a'methodoffdewaxing process which `is capable of lhandling la wider lubricating and other `wax bearing oils for' the varietyfofvoils and in which lower filtering pres-'j purpose of lowering the'cold test properties 4of the sure may be used.

same;- 4 i Various Y other objects andadvantages of the In'the previous Patent No.'1,509,325,1 granted to` invention will appear Aas this'descripton proceeds. `5

myself andvWilliarn J .`-Ryan, September 23, 1924, The accompanying diagrammaticdrawin'g fis We have described and claimed broadly the sepa.- n illustrative of a typical plant layout 'for operatration of wax from wax bearing oils by the use of a ing according tothe process of `this invention, but wax` adherent mediumof a flocculent nature, such it is Vtojbe understood, howevergthat the use of the l0 as vfullers earth, kieselguhn and filter-aid maprocess is not confined to this particular struc- 10 terials derived from diatomaceous'earth or porous tural layout. n o and cellular siliceous mineral deposits or the like, 'In the drawing, the supply of diluted'wax bear-L which facilitates the separation and congealing of ing oil is indicatedat I and is providedwith a the wax from the oil uponjchilling of the same.` gravityv outlet 2 controlled bya valve 3 for charge 1li In said4 patent, the wax` adherentimedium is ingthe first chiller' 4 whichfisjacketed for the 15y l added tothe oil'before chilling and, during ,the circulatio'nof cold brine or other refrigerant, chilling, the wax congeals upon the particles' of as indicated at 5, and provided .with anagitator the wax adherent medium forming crystals or 6 having a drive pulley'ta for circulating the oil.

globules of Wax which lodge upon the vfilter sur- From the Chiller '4 the dilute oil flows through 2'0- face during filtration while permitting the dilute the pipe 'I to thesecond chillerj which`is`like 20 chilled oil to 'flow through the filter surfaces Wise brinejacketedand provided With'a'n agifreed from'thewax. j tator. i 4

MyA presentinvention contemplates the addi- The oil discharge-d lfrom the chillerffiowsv tionjof filter-aidmaterial or lfinely-divided solid through the pipe 9 t0 the Dump l0 and is pumped 25. granular material to Wax-.bearing oil after chilling through the coils Il of the `refrigerantchamber 2'5`v and lc ongelation of itsV Wax constituents. The" l2 While C01d`bri11e 0r 'other refrigerant oWS filteraid material *isv mixed` with n the cold; and throughthese coils in opposite direction from the y congealed wax, andthereupon the resultingjmix compressor to the coils I I and thence around the ture"l of filter-aid `material and solidified waxv is Chillers 8 and land back to the COmDIeSSOr. ,Y separated from theoil; 'Aghopper I3 provided with a worm discharge 30 The addition 'of the'v filter-'aid or granular-mar lfeedlll contains the wax adherentf'medium or terial to the cold mixture of oiljand congealed 'waxl filter Aaid,.and isr located to supply this'material' faciiitates thesubsequentseparation of the wax' tothe'mixing `tankjli provided with anagtator by filtration or otherwise. I6,in Whichthe `wax adherent medium is mixed 'y :have found `that with certain types of wares,v Withthe dilute Achilled Oil from the refrigerator l Se' particularly: those which solidify yin an inter- I2 tocoat the'congealed Wax particles therein. mediate phase between the true amorphous and 'After throughmixng'rr the tank lthe'chilled tre crystalline wax, that the addition of the wax oil with the particles rof ,solidified or congealeld adherent medium or lter aid, after the `chilling Wax'coated with the waxadherent medium flows i0 or v solidication of the wax particles, causes the through the pipe` I1 to the control boxj I8 which d filter aidto coat the solidparticles 'of the chilled controls the feed ofthe vmixture to the filter I9, wax and to serve as a separating medium between which is 'preferably a continuous filterofthepresthe particles of wax on the filtermedium voffering sure or suction'typewell known to persons skilled paths or cleavage planes between theparticles of in this art. i l5A solid wax, throughf which the dilute oil may flow y to separate it from the wax'.- f v andfilteraid flows through the poresof the filter YIt is, therefore, anobject of the present inven`` medumi'the Solid partieleof Wax and thefllter tion 'to provide a process'for the dewaxi'ng of oils .aid are deposited on the lter Surface with `the in which the wax adherentmedium is addedto the filter aid. between .and Separating the WaX 119211,-

' As the chilled oil'mixed with thesolidifled `vvax 45 i oil after. chilling of the' same to coat 'andsepae ticleapermitting-'more rapid flow ofthe oilthere-- 50" Another object of 'jtheinvention is to improve l'hewax freed oil is discharged through'the 'pipe the rate' of filtration .of certain chilled Waxy bear- 20 to anyA desired point, where advantage may be ing oils.v taken of its' low temperature toi assist in the 'chill- Another'object of the'invention is tojprovide a ing of the'inconi'ng oil or the brine'and the'solid 55" separates the wax adherent medium fromthe Vthe separated filter aid being returned to the tank I3 for reuse.

Reference may also be made to' the drawing which illustrates in moredetail thevmethod of recovering the filter-aid material as described in the foregoing patent. y

Thus, the sone wax and nner-aid material as! cumulating in the storage tank 22 may be conducted to a. trough 23 provided with a conveyor screwA and by whichfmeans it is'introduced to awashing tank 24.

A suitable solvent or washing. liquid is 'conf ducted from tank 2.5 to a heater 26. The solventv may be naphtha, alcohol or any other liquidcay pable of dissolvingthefwax .orother congealed hydrocarbons; The ,heated solvent discharges throughthe tube 21 into the trough 23, the mixing being accomplished by the conveyor screw.

Ifdesired, the heated solvent may be discharged through `thetube 28 directly into the washing tank 24'or the heated solvent may be discharged into both the troughand the tank.

Tank 24l swell'insulated and may be provided with heating coils 29. The cake of wax and iilteriaid material'is dissolved bythe heated sol- 30 wherein thev mixture is reduced to the `desired liquid or solvent is'separated from the wax or 34 from which it may be conducted to suitable vent and the dissolving action is assisted by the stirring', mixing or agitation of the cake and solvent 'within ther Washing tank. t

f The mixture ows from the tank 24 to a'cooler temperature, such temperature preferably? being sufficiently low to prevent `vaporization of the hydrocarbons. From the cooler 30, the cooled mixture is conducted to a. filter'3l. This lter liquid', the liquid being al mixture of the solvent and wax or .other hydrocarbons. l

' 'The liquids. flow from the 'filter throughvthe pipe'32 to a storage tank 33 and 'the washing other extracting hydrocarbons by any other-'well known methods of distillation and reiini'ng.' .The

wax adherent medium Vforms a cake inthe lter pressand such cake is discharged into the hopper storage m'eansior' reuse. Y

'The term' ".diluted oil as referred to in this specification will be" understood to include any oil which remains fluid and pumpable at dewaxing temperatures, whether the diluent is con?l tained in the oil in its natural statefr-is found therewith asa result f the ymanufacturing `proc.

essor isarticially added thereto. A Vsuitable diluent `may comprise naphtha, alcohol .or any other liquid suitable for' lowering the cold test and. viscosity, and decreasing the speciflcgravity of the hydrocarbons being. treated, as, disclosed, for example,l in the above Patent 1,509,325.

. Various modifications and changes may beresorted to in the detail steps of the process without departing from the spirit of my invention or the scope ofthe appended claims.

,'Iclaim: Y

n1 "I'h`e process of lowering the cold test of lubricating oils which consists in combining a diluentwith lubricating .oil stock containing wax, `chilling the same to congeal the waxand adding thereto a-'comminuted wax adhrent medium, the vdiluted stock other the wax `re' `maining liquid and then separating the chilled associated wax and wax adherent medium from the liquid mixture.

2. A process of lowering the cold test of lubrlcating oils which includes the operations of combining a diluent with lubricating oil stock, chilling the mixture thus produced to congeal the wax, adding a wax adherent medium to the chilled diluted stock, then separating the chilled associated wax andv waxV adherent medium from the liquid mass, then dissolving the wax that has been congealed from the Wax adherent medium With-.a solvent and separating the wax solution .from the waxadherent medium.

adherent medium from this solution whereby the wax adherent medium may -be reused in 'a similar cycle `of operations. l

4. In the removal of wax from a. diluted waxcontaining oil, the improvement that comprises chilling the'. diluted oil then mixing the same while chilled withja i'lnely divided granular ma.- terial, and separating vthe oil from the wax and granular material. f

5. 'I'he method of lincreasing the rate ofr filtration of a ywax bearin'gloil wherein the wax-is congealed by chilling, which comprises. adding a. filter aid to the chilled oil to separate the wax particles andpa'ssingr the treated oil through a continuous filterff f 6. The methodof dewaxing oil which comprises chilling a diluted wax bearing'o'il mixture adding a'. wax Aadherent medium'of the character of 7a nner-aia matenai including funers 'earth Vand'- kieselguhr tothe chilled oil, passing the chilled oil through` a yfilter to s epara'te'the wax and wax adherent medium from thev oil and separatingthe wax from'the wax adherent medium'. t;

7." In` theremoval'of waxv from vwax-containf` ing oilth'e` improvement that' comprises chilling the oil, then mixing the samewhile 'chilled' .with

a filter-aid material,l and ltcrlilgthe waxand filter-aid'materiaifrom the"011.i t f `8. The processof separa wax from. v\na,`x containing oil comprisingr chilling. the oil tofa temperature suilicient toprecipitate wax ithere-` from, and removing said wax by 4iltration with the aid of viinel'y-"divided solid vmaterial adhering to and vforming a coating` on theparticl'es of the precipitated wax saidiilter-aid material being added to the oil after chilling.

9.-" 1he processof 'removing fromr petroleum oil, wax which solidies upon` chilling in an iii-'- termediate 'phase between the true 'amorphous and true crystalline forms, comprising- .chilling said'il, mixinga finely-divided lter-aid material therewith, and fllterin'gthe .oil from the wax and wax-adherent medium. l

.110.'1he process of removing wax from waxco'ntaining oils comprising diluting said oil, chillfv ing the diluted oil to a temperature siifllciently` low 'to precipitate .waxy constituents, adding to and agitating with the lchilled oilA `a'iinely divided ed;megared-materie.fam #hw-f w l1. The process of separating wax from Waxoontaining oil which comprises chilling the oil to a temperature suiiicient to precipitate Wax` therefrom, then mixing a finely-divided `solid filter-aid material With the chilled oil whereby a suspension of precipitated Wax and filter-aid material in oil is formed, and filtering the suspended Wax and filter-aid material from the oil.

12. In dewaxing hydrocarbon oil by ltration,

the method of increasing the rate of filtration of solid Wax from a chilled mixture containing oil and' solid Wax Which comprises adding a filteraid material to the chilled mixture, and then passing the cold mixture through the filter wherein the solid wax and lter-aid material is sep-- arated from the oil in the form of a lter cake.

JAMES W; WEIR. 

